Glow discharge tube for code display

ABSTRACT

A glow discharge tube for code display in which a plurality of cold cathodes in the shape of a plate comprising a segmented portion forming a luminous code and a lead connected to that portion are piled up with a window-frame-shaped insulating plate interposing between each layer to construct a cold cathode structural body and interposing the said lead between the said insulating plates in order to prevent a negative glow at the said lead portion.

United States Patent 51 3,641,383 Tagawa Feb. 8, 1972 [54] GLOW DISCHARGE TUBE FOR CODE [56] References Cited DISPLAY UNITED STATES PATENTS m] Invent Takmukmh" Japan 3,244,923 4/1966 Milliken ..3|3/109.5 [73] Assignee: Matsushita Electronics Corporation, 3,517,257 6/1970 Kuchinsky et al. ..3l5/ l6 Osaka, Japan Primary Examiner-Raymond F. Hossfeld Fllfid' 1969 Attorney-Stevem. Davis. Miller& Mosher [211 Appl. No.: 859,519

[57] ABS'IRACT m Foreign ADM p i n A glow discharge tube for code display in which a plurality of cold cathodes in the shape of a plate comprising a segmented Sept. 25, 1968 Japan ..43/70664 portion forming a hummus code and a lead connect m that t 3! portion are piled up with a window-frame-shaped insulating plate interposing between each layer to construct a cold [52] US. Cl. ..3l3/l09.5, 313/210, 3 l3/2l7, cathode Structural body and inmrposing the jd d between 315/169 R, 30/336 the said insulating plates in order to prevent a negative glow at [51] Int. Cl. .1101; 61/66 the Said lead portion FieldofSearch ..3l3/l09.5,2l0,2l7;3l5/169; H 349,??

5 Claims, 7 Drawing Figures PATENTEUFEB 8:972 8.641.383

sum 1 or 4 INVENTOR BYM f M ATTORNEYS This invention relates to a glow discharge tube for code display.

It is well known that a glow discharge tube for code display in which a plurality of segment-shaped cold cathodes are arranged in a mosaic and various luminous codes produced by the cathode glow are produced by selectively connecting the cold cathodes to an anode. In such a glow discharge tube, a plurality of segment-shaped cold cathodes are usually arranged within a plane. Such an arrangement is advantageous in that there is no danger of misreading the luminous code, whether the viewing angle to the luminous code is large or small. However, the number of segment-shaped cold cathodes which can be arranged in a limited area is relatively small and the kind of luminous codes which can be set up is naturally also limited.

One object of the present invention is to increase the number of luminous codes which can be set up.

Another object of the present invention is to produce a luminous code having no break, and yet another object is to prevent any undesirable luminescence occuring at the lead to the cold cathode. A further object of the present invention is to provide a composite glow discharge tube.

A glow discharge tube according to the present invention is comprised of a plurality of cold cathodes piled up by inserting a window-frame-shaped insulating plate between each layer, an anode disposed opposite to the cold cathodes, and an envelope hermetically sealing these electrodes together in an inert gas such as neon or argon, in which each cold cathode is comprised by a segmented portion disposed on a mosaic pattern so as to produce a luminous code corresponding to a selection of each conducting cold cathode to the said anode and a lead portion connected to the segmented portion, wherein the lead portion being characterized by the fact that it is interposed between the said insulating plates so as to be shielded from the said anode.

Now, the glow discharge tube for code display according to the present invention will be described in detail with reference to the accompanying drawings, in which:

FIG. 1 is a perspective exterior view of an embodiment of a glow discharge tube according to the present invention;

FIG. 2 is a top view showing the state when an outer cover (bulb) shown in FIG. 1 is removed;

FIG. 3 is an exploded view of the device shown in FIGS. 1 and 2;

FIGS. 4 and 5 are circuit diagrams of conventional display devices with three figures,respectively;

FIG. 6 is a partially broken perspective view showing the main portion of another embodiment of the present invention; and

FIG. 7 is an exploded view of the device shown in FIG. 6.

Referring to FIG. 1 and FIG. 2 which shows the state when a bulb l is removed, cold cathode terminal pins 2 and an anode terminal pin 3 are provided hermetically penetrating a stem insulating plate 4. The stem insulating plate 4 constitutes an envelope together with the bulb 1 having a viewing window 5 and an electrode assembly 6 facing the window 5 is hermetically sealed in the envelope together with an inert gas such as neon or argon. The electrode assembly 6 is comprised, as can be seen from FIG. 3 showing the exploded view of the device, of eight cold cathodes K,K,, piled up on the stem insulating plate 4 in two-row-four-layer interposing window-frameshaped insulating plates H,I-I, having a see-through hole made of mica or ceramic between the layers and a transparent anode A in the shape of a mesh or a lattice placed adjacent to and facing the group of the cold cathodes. Here, it is desirable to use such opaque material as ceramic as the uppermost insulating plate H.,, and the anode A may be placed at the lower side of the cold cathode group, that is, adjacent to the stem insulating plate 4, in which case the anode can be an opaque material. Each of the cold cathodes K,K,, is respectively formed with one metal plate, and consist of respective segmented portions k,-k,, which contribute to the production of a luminous code and respective band-shaped lead portions L which extend toward the inner end of the cold cathode terminal pins 2. The segmented portions k,-k,, are distributively arranged corresponding to a predetermined plane mosaic pattern so as to form various luminous codes by the glow discharge when they are selectively conducted to the anode A. The insulating plates I-I,l-I, support the cold cathode by holding in a sandwichlike fashion almost all portion of the cold cathodes I(,l( except for the segment portions k,-k,, -between them and at the same time they electrically shield the interposed portion from the anode A. Thus, the segmented portions k,k, of the cold cathodes K,l(,, are viewed mainly in -the see-through hole W, as shown in FIG. 2, and they can be viewed through the viewing window 5 of the bulb 1. Reference mark S indicates insulating rods which are used as a guide to position the parts when the cold cathodes are piled up in the sandwich construction; rods S stand up from the stern insulating plate 4. P indicates insulating bushings.

A luminous CODE HAVING NO BREAK CAN BE PRODUCED BY means of the above-described construction, since there is a gap corresponding to the thickness of the insulating plate between each of the plurality of cold cathodes piled up. Thus, the mutually adjoining portion of the segmented portion of each cold cathode can be abutted when viewed from their viewing axis or can be arranged in layers in the viewing direction. Furthermore the kind of luminous codes which may be set up can be increased, since a portion of the device is three-dimensionally constructed. Moreover, there is no danger of a negative glow taking place at the lead portion of each cold cathode, since this portion is shielded from the anode by the insulating plate, and also the segmented portion can be rigidly supported.

In another embodiment of the present invention, a plurality of electrode structural bodies such as described above are sealed in an enveloped. Such a composite type glow discharge tube is usable in a display device with multiple figures employing such a time division driving circuit as shown in FIG. 4 which shows a time division driving circuit of a prior art arrangement. Now, the operation of the circuit shown in FIG. 4 will be briefly described. Each of glow discharge tubes for code display T T and T,, which display numbers of 1, l0 and multiples, respectively, has cold cathodes K K,-K which are formed in the shape of figures 0 respectively and 1-9, and an anode disposed facing towards those cold cathodes. Each of the cold cathodes K K,K of each of the tubes T,, T, and T is connected to corresponding ones of busbars L L,L,, so that the cold cathodes with the same code are together connected to the corresponding busbar while three anodes A,, A, and A selectively are connected to the positive side of a power source E through a switch S, and a load resistance R. The negative side of the power source E is connected to a switch S for selectively connecting the busbars L L,L to the power source E. The switches S, and S, are coupled to a driving circuit C and they are synchronously driven by the circuit. In the above construction, if the switches S, and S successively repeat with an extremely short time period such a connection as, for example, the switches S, and S being switched to the respective terminals 1 and a, then [I and b, and then to III and j, the tubes T,, T, and T display a numeral 0l9as a whole. In the same way, if such a connection as, for example, the switches S, and 8, being switched to the respective terminals I'and b, then to II and j, and then to III and a is successively repeated, the number is displayed.

It can be seen that one composite type of glow discharge tube can be utilized in place of the three glow discharge tubes for code display T,, T, and T shown in FIG. 4. One illustrative prior art arrangement of such a composite tube is shown in FIG. 5. In the figure, reference mark T indicates a glow discharge tube in which three display unites 1,, t and 1 are enclosed in a common bulb. Each display unit of the tube T is comprised of a plurality of segment-shaped cold cathodes which are arranged in the form of a mosaic, and the corresponding cold cathodes of each of the display units are connected to respective busbars, then each busbar is connected to a switch S through a matrix circuit M for code production.

According to the present invention, it can provide such a composite-type glow discharge tube for code display which is Suited to a display device with multiple figures having such a circuit as shown in FIG. 5, and such device is described hereinunder,

Referring to FIG. 6, there are shown representatively almost all parts of a cold cathode structure of a display unit t and a portion of display units t and t which are disposed in the area adjacent to the display unit t Segmented 11-18 of eight of eight cold cathodes forming the cold cathode assembly of the display unit 2 are arranged in a predetermined mosaic pattern so as to form various codes by means of a selective combination of them. By this arrangement a plurality of display units are integrally formed by mutually connecting the corresponding segmented portions at their end portions with a lead portion in such way that the segmented portion 11 is integrally formed with a corresponding segmented portion 21 of the display unit t through a lead portion 31 and-similarly the segmented portion 12 of the display unit t is integrally formed with a corresponding segmented portion 22 of the display unit through a lead portion 32, etc. Each lead serves not only as a busbar, but also as a mechanically supporting member for each cold cathode. That is, as is shown in FIG. 7, lead portions 31 32, 33 and 34 are piled up by alternately interposing a window frame shaped insulating plate H made of, for example, mica or ceramic. Insulating rods standing up from a stem insulating plate 4 rods S as a guide to locate the position of the parts at the time of the said setting up. Each insulating plate H is provided with a hole W to expose to an anode A the segmented portion of the cold cathode where the negative glow is wanted and has wider frame portions than the lead portion of the cold cathode which frame portions cover the lead portions of the cold cathodes under the insulating plate, projecting toward the inside of an opening of the assembled cold cathodes. Therefore in his case, a negative glow is produced only within the range indicated by the hatching in FIG. 6. The independent anode A is provided to each display unit and is independently led out to the exterior of the bulb, while for the 3 X 8 segmented portions which constitute the main portion of the cold cathode consisting of the three display units are provided eight lead wires in total in the case of this embodiment. A shield 50 which is provided between the display units to prevent the electrical and optical interaction between the display units is mounted on the insulating plate H by inserting its leg into a slit 51 of the insulating plate H. The electrode assembly is hermetically sealed into an envelope (not shown) with an inert gas, and when it is viewed through a viewing 'window of the envelope, the segment portions of the cold cathode group are viewed with an such arrangement as is shown by the hatching in FIG. 6.

What is claimed is:

I. A glow discharge tube for code display, comprising: a plurality of cold cathodes arranged in layers, each having a segmented portion arranged in a mosaic pattern, each segment comprising a portion of a luminous code character, a plurality of said segments cooperating to form a complete luminous code character; a lead portion connected to said segmented portion; window frame shaped insulating plates interposed between said cathode layers and shielding said cathode layers from each other, said plates having frame portions which are wider than and cover said cathode lead portions; an anode disposed in and T to said layered cathodes and insulated therefrom by said insulating plates: and an envelope hermetically sealing said layered cathodes and said anode together with an inert gas? 2. A glow discharge tube according to claim 1, wherein said segmented portion and said lead portion are formed by a single metal plate, said segmented portion extending from and being mechanically supported by said lead portion- 3. A glow discharge tube for code display according to claim 1 characterized in that said plurality of cold cathodes are arran edin two rows and a Pluralit of layers.

4. A gow discharge tube or c e display according to claim 1, characterized in that at least two of said segment portions are disposed in layers at their mutually adjoining portions when they are viewed from their viewing axis.

5. A glow discharge tube for code display according to claim 1, characterized in that a plurality of display units are formed by arranging each segmented portion of said cold cathodes into a plurality of regions in mosaic and said lead portions are disposed between said display units.

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 2 641 383 Dated Februarv 8. 1972 Inventor (5) Ha Z 5 me I agawa It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 23, "and T" should read facing relation Signed and sealed this 13th day of June 1972..

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Commissioner of Patents IAttesting Officer USCOMM-DC 60376 P69 fi' 11.5 GOVERNMENT PRINTING OFFICE: 1969 0-366-334 FORM P0-105O (10-69) 

1. A glow discharge tube for code display, comprising: a plurality of cold cathodes arranged in layers, each having a segmented portion arranged in a mosaic pattern, each segment comprising a portion of a luminous code character, a plurality of said segments cooperating to form a complete luminous code character; a lead portion connected to said segmented portion; window frame shaped insulating plates interposed between said cathode layers and shielding said cathode layers from each other, said plates having frame portions which are wider than and cover said cathode lead portions; an anode disposed in facing relation to said layered cathodes and insulated therefrom by said insulating plates; and an envelope hermetically sealing said layered cathodes and said anode together with an inert gas.
 2. A glow discharge tube according to claim 1, wherein said segmented portion and said lead portion are formed by a single metal plate, said segmented portion extending from and being mechanically supported by said lead portion.
 3. A glow discharge tube for code display according to claim 1 characterized in that said plurality of cold cathodes are arranged in two rows and a plurality of layers.
 4. A glow discharge tube for code display according to claim 1, characterized in that at least two of said segment portions are disposed in layers at their mutually adjoining portions when they are viewed from their viewing axis.
 5. A glow discharge tube for code display according to claim 1, characterized in that a plurality of display units are formed by arranging each segmented portion of said cold cathodes into a plurality of regions in mosaic and said lead portions are disposed between said display units. 